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FAIR VALUE MEASUREMENTS - Narrative (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended |  |
--- | --- | --- | --- | ---
Sep. 30, 2025 | Mar. 28, 2025 | Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2023 | Sep. 29, 2025 | Dec. 27, 2024
Impaired Long-Lived Assets Held and Used [Line Items] |  |  |  |  |  |  |
Asset impairment charges |  |  | $ 214,386 | $ 0 | $ 0 |  |
Long-lived assets, carrying value |  |  |  |  |  |  | $ 250,966
Long-lived assets, fair value disclosure |  |  |  |  |  | $ 50,800 | $ 123,233
Impairment of definite-lived intangible assets | $ 37,510 | $ 92,397 | 129,907 |  |  |  |
Asset impairment charges | 27,829 | 31,766 | $ 59,596 | $ 0 |  |  |
Impairment of right-of-use assets | $ 1,378 | $ 3,570 |  |  |  |  |
Impairment, Intangible Asset, Finite-Lived, Statement of Income or Comprehensive Income [Extensible Enumeration] | Asset impairment charges | Asset impairment charges | Asset impairment charges |  |  |  |
HDPE Business |  |  |  |  |  |  |
Impaired Long-Lived Assets Held and Used [Line Items] |  |  |  |  |  |  |
Asset impairment charges | $ 66,717 | $ 127,733 | $ 194,450 |  |  |  |

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